Book/Report

FZJ-2018-03441

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Erarbeitung einer gefügeabhängigen Beschreibung des Hochtemperaturverformungsverhaltens des Turbinenschaufelwerkstoffes in 738 LC

Londschien, B. (Corresponding author)FZJ* ; Penkalla, H.-J.FZJ* ; Schubert, F.FZJ* ; Nickel, H.FZJ*

1991
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/18886

Report No.: Juel-2466

Abstract: Since more than 15 years, the nickel-base alloy IN 738 LC is used for stationary gas-turbine blades because of its good high temperature strength coupled with acceptable hot corrosion resistance. The high strength in the temperature range 700° to 1000°C results primarily from the intermetallic phase $\gamma$'= Ni$_{3}$(Al, Ti). The $\gamma$' precipitates restrict the motion of the dislocations. The high temperature deformation behaviour has been correlated with the morphology of the $\gamma$' precipitates. It was found that the deformation rate in short term creep experiments (up to 1000 hours) depended on the initial microstructure of the cast alloy. The microstructure could be characterized by $\gamma$' particle size and distribution in the matrix. A heat treatment was applied with the aim of producing a more stable microstructure, so that the long time creep behaviour does not depend so strongly on the initial microstructure. The structure development in the experiments could be described by the growth of the $\gamma$' precipitates, calculated from the diffusion rates of aluminium and titanium in the nickel matrix. During operation, the turbine blade is loaded with a multi axial stress comprising the centrifugal force, the thermally induced stationary and instationary stresses, and the bending stresses from the gas flow. It was shown in strain-rate controlled tension-torsion test on hollow round samples, that the multiaxial stress-strain behaviour could be calculated using the invariant theory for isotropie materials with a comparative stress value from the uniaxial creep experiment, applying the von Mises theory. This mathematical model is useful for calculating the life time for a-turbine blade which is multiaxially loaded.

---

Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

---

Database coverage:

---